The majority of students who receive Educational Maintenance Allowance (EMA) rely on this support, it has been revealed.
A survey by the University and College Union found that 70 per cent of EMA recipients would drop out if this benefit is withdrawn.
This comes as MPs are preparing to vote on the issue, with the coalition government planning to axe EMA support.
Almost two-thirds of respondents said they rely on EMA as they receive no financial support from their family.
Dave Prentis, general secretary of Unison, said scrapping these payments is a "vicious attack" on young people and their families.
"EMA is not pocket money, it is vital support to the poorest students and allows them to buy books and pay for travel to college. Without this support many young people will be forced to drop out, or rely on their families to step in," he commented.
"For many families already facing pay freezes and job cuts this will simply not be possible. MPs must do the right thing and vote for the government to rethink its savage plans."